Perfluoroacyl peroxides are commonly made by stirring aqueous hydroxide and hydrogen peroxide (or metal peroxides such as Na.sub.2 O.sub.2) with an acyl chloride or fluoride dissolved in an organic solvent. Reaction times typically range from about 1 minute to about 60 minutes.
Perfluoroacyl peroxides are generally thought of as too hydrolytically unstable to be useful as initiators in the presence of water. Thus, as the intensity of stiring or emulsification is increased in the synthesis of a perfluoroacyl peroxide, a point may be reached at which peroxide yields decrease as a result of competing hydrolysis reactions. Ultrasonics exposure, in particular, is known to have an accelerating effect on the hydrolysis of organic compounds.
U.S. Pat. No. 4,075,236 passes acid chloride, hydroperoxide, and aqueous alkali metal hydroxide through a series of two mechanically stirred reaction vessels to produce peroxyesters of the formula R.sub.y -(C.dbd.O)OO!.sub.n R'. Structures R and R' are left quite general in the claims but it should be noted that all specific examples contain only carbon and hydrogen. Although it appears that this patent claims accelerated reaction rates, the examples are written so that exact reaction times are not mentioned. (Assuming, however, that the 10 gallon reactor size discussed in connection with impeller design, at column 4 line 20, applies to both reactors then the reaction times in the experimental examples would be about 4 minutes).
DD 128663 passes acid halides, hydroperoxide, and aqueous alkali through a series of reactors or possibly a single cascade reactor with intense mixing. This produces peroxyesters of the formula R(C.dbd.O)OOR', where the R and R' groups are again exemplified by compounds containing just carbon and hydrogen. Short reaction times of 0.5 to 15 minutes are achieved by using elevated reaction temperatures (40 to 95.degree. C.) in conjunction with a series of vessels to control the heat of reaction.
In U.S. Pat. No. 5,021,516, in which HFPO oligomerperoxides were made from HFPO oligomer acid fluorides, carbonates, and 30% hydrogen peroxide, reaction times were 10 minutes to 7 hours.